The present invention relates generally to gas sampling with an airway adapter providing a connection between an endotracheal tube, an artificial breathing system and a gas sample analyzer. In particular, this invention relates to an airway adapter that permits the use of a closed suction catheter system on the patient without disconnecting the gas analyzer from the patient.
During surgery or in an intensive care unit, patients may be mechanically ventilated through an endotracheal tube. Since it is often desirable to measure the mechanical and chemical characteristics of the gases going to and coming from the patient, an airway adapter may be inserted in the line between the patient's endotracheal tube and the ventilator to provide a gas sample port for the gas analyzer. Some earlier designs of airway adapters are described in U.S. patent application Ser. No. 389,853, filed Aug. 4, 1989.
It is sometimes necessary to remove mucus or other material from the patient's mouth, trachea, and other air passages. One removal method is to draw the material into a suction tube inserted into the patient's trachea through the endotracheal tube. These systems are called closed suction catheter systems or closed tracheal suction systems. One such system is the model 2205 system sold by Ballard Medical Systems.
If the gas going to and from the patient must be sampled and analyzed during ventilation, an adapter must be inserted in the line between the ventilator and the endotracheal tube to provide a gas sample port. A filter may be disposed in the airway adaptor to prevent foreign matter from entering the gas analyzer. In airway adapters according to some earlier designs, the filter lies in the flow path between the endotracheal tube and the ventilator.
If a suction catheter system is connected to a gas analyzer adapter of this configuration, however, the adapter's filter will block the path of the suction tube. Thus, in order to insert the suction tube into the patient, the gas analyzer adapter must first be removed from the endotracheal tube. In addition to requiring an extra operational step in a busy operating room or intensive care unit the removal of the adapter interrupts the flow of oxygen and/or anesthetic to the patient.